The present invention relates to a computer controlled method of controlling internal climate comfort by natural ventilation in a living room in a building occupied by human users, said room being connected with the outside of the building through at least two external openings with associated passive ventilation devices, which are individually adjustable by means of associated operator units and being further connected through at least one internal opening with another room of the building, whereby a target air exchange rate for said living room is calculated from a constant physical parameter of the room and measured parameters relating to wind load or air pressure and :to difference between indoor and outdoor temperatures.
Computer controlled methods and systems for heating, ventilation and air conditioning in buildings are well known and conventionally based on the use of active heating, ventilation and air humidity control devices. Various designs of such systems are described e.g. in U.S. Pat. No. 4,567,939, U.S. Pat. No. 4,931,948, U.S. Pat. No. 5,215,498, U.S. Pat. No. 5,348,078, U.S. Pat. No. 5,803:,804, DE-A-196 00 694 and EP-A-0 585 133.
It is well-known that such an active indoor climate adjustment does usually not function in the best possible way under variable outdoor climate conditions and furthermore is attended by a considerable energy consumption.
On this background, recent years have shown an increased interest for using controlled natural ventilation for indoor climate adjustment. By controlled natural ventilation is in this connection meant adjustment of the indoor climate in a building by use of natural variation in outdoor and indoor climate variables and by ventilation air supply through adjustable openable parts or sections of building facades. Such openable ventilation devices are typically window sections in the building facades, however, they may also comprise other forms of openable facade parts, such as adjustable ventilation dampers, grids and similar devices.
Experimental projects to illustrate the possibilities of natural indoor climate adjustment by use of intelligent computer systems are described e.g. by J. I. Kindangen in his report xe2x80x9cArtificial neural network and naturally ventilated buildingsxe2x80x9d in Building Research and Information, Vol. 24, no. 4, 1996, and by D. Azzi, G. S. Virk, A. K. M. Azad and D. L. Loveday in a conference paper xe2x80x9cTowards the xe2x80x9cintelligent buildingxe2x80x9dxe2x80x9d at the 18th AIVC Conference in Greece in 1997, whereas control strategies herefor are described by A. J. Martin in xe2x80x9cControl of Natural Ventilationxe2x80x9d, BSRIA Technical Note TN 11/95. The purpose of these experiments has essentially been to describe different parameter models for pure computer controlled adjustment of various forms of adjustable heating, ventilation, shading and humidity control devices.
U.S. Pat. No. 5,226,256 discloses a method of the above type, by which passive ventilation devices in the form of windows can by means of sensors adapted for the purpose be adjusted in dependence of indoor climate variables, such as temperature, relative air humidity and CO2 content and external parameters as for instance noise conditions in the surroundings and the airflow velocity near a window. For this adjustment each window is associated with a microprocessor which can also be controlled from a portable or stationary remote control unit just as all windows can be controlled jointly from a central control unit in a control room.
On the basis of this prior art it is the object of the invention to provide an optimized method for automatic computer controlled ventilation of living rooms in buildings, by which inconveniences, such as the feeling of draught under cold weather conditions, resulting from the supply of fresh air to a living room by the flow of air through external openings such as opened windows can be significantly reduced and an increased and well distributed internal climate comfort can be obtained.
To fulfil this object the method according to the invention is characterized in that an adjustment parameter for the operator unit of each of said passive ventilation devices is determined to provide an air exchange to the room on the basis of said target air exchange rate, said adjustment parameters being further modified by application of a set of comfort functions, which are established individually for each of said external and internal openings, said comfort functions being determined to take account at least of outside and inside temperature, air exchange and wind load or air pressure and the comfort functions of said set being weighed by fuzzy optimization to produce optimized and substantially equally distributed comfort conditions in positions in the living room adjacent each of said openings.
Whereas some principles of general application of fuzzy logic operations to building climate control have been described in a publication by the Frauenhofer Institute for Information and Data Processing IITB TH. Bernard and H.-B. Kunze xe2x80x9cMulti-objective Optimization of Building Climate Control Systems using Fuzzy-logicxe2x80x9d, the invention is based on the recognition of the fact that no universal model can be realistically applied to describe human comfort perception, but that normalized performance criteria can de described as fuzzy membership functions, which can be optimized by the use of fuzzy optimization
Preferred ways of implementation of the method are stated in dependent claims 2 to 6.
According to the invention the method is carried out by means of a computer controlled system for natural ventilation in a living room in a building occupied by human users, said room being connected with the outside of the building through at least two external openings with associated passive ventilation devices, which are individually adjustable by means of associated operator units and being further connected through at least one internal opening with another room of the building, said natural ventilation being determined from a constant physical parameter of said living room and measured parameters relating to wind load or air pressure and difference between indoor and outdoor temperatures to approximate a target air exchange rate for said living room, said system being characterized by comprising a computer device and sensor means for sensing said wind load or air pressure and said temperature parameters and inputting corresponding wind and temperature data to said computer device, said computer device having means for storing a target air exchange rate for said living room, means for determination of an adjustment parameter for the operator units of each of said passive ventilation devices to provide an air exchange to the room on the basis of said target air exchange rate, means for establishing a set of comfort functions individually for each of said external and internal openings to take account at least of outside and inside temperature, air exchange and wind load or air pressure, and means for modification of said adjustment factors by application of said set of comfort functions weighed by fuzzy optimization to produce optimized and substantially equally distributed comfort conditions in positions in the living room adjacent each of said openings.
Preferred embodiments of the system according to the invention are stated in dependent claims 8 to 11.